passing a temporary(rvalue) to a function which expects an lvalue

posted Dec 5, 2014, 7:56 AM by Javad Taghia

Or, if you have a C++11-compliant compiler, can use the so called universal reference approach, which, via reference collapsing rules, can bind to both lvalue and rvalue references:

#include <iostream>
using namespace std;

struct Person {
  int age;
  Person(int _age): age(_age) {}
};

template<typename T> // can bind to both lvalue AND rvalue references
void printAge(T&& person) {
   cout << "Age: " << person.age << endl;
}

int main () {
  Person p(50);
  printAge(Person(50));  // works now
  printAge(p);
  return 0;
}

Or, in C++14,

void printAge(auto&& person) {
   cout << "Age: " << person.age << endl;
}
void printAge(const Person &person) {
   cout << "Age: " << person.age << endl;
}
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